From Adobe APSB12-11, "Adobe released a security upgrade for Adobe Photoshop CS5.5 and earlier for Windows and Macintosh. This upgrade addresses vulnerabilities that could allow an attacker who successfully exploits these vulnerabilities to take control of the affected system.

Adobe has released Adobe Photoshop CS6, which addresses these vulnerabilities. For users who cannot upgrade to Adobe Photoshop CS6, Adobe recommends users follow security best practices and exercise caution when opening files from unknown or untrusted sources."